New Study Finds Fungi (Molds) May Worsen Alcoholic Liver Disease

A new study by the National Institute on Alcohol Abuse and Alcoholism (NIAAA) had shown that intestinal fungi (molds) such as a Candida may contribute to the development of alcoholic liver disease (ALD or Alcoholic fatty liver disease, Alcoholic hepatitis). A disease that is the 12th leading cause of death in the U.S. and accounts for approximately half of all liver disease deaths.

ALD is characterized by fat deposition in liver cells, inflammation and mild scarring of the liver which is end-stage liver disease, or cirrhosis (liver cell death). ALD has previously been associated with bacterial overgrowth in the intestines, as well as a shift in the types of bacteria found there. Until now, little was known about the role of intestinal fungi in ALD.

Researchers at the University of California, San Diego and the J. Craig Venter Institute in Rockville, Maryland, found that fungi (molds) flourished in the intestines of mice with chronic alcohol exposure. The most common fungi found in the human intestine are Candida species, Saccharomyces cerevisiae, and Malassezia species in which the researchers noted that fungal overgrowth exacerbated alcohol-induced liver disease.

“Not only is this the first study to associate fungi and liver disease,” said senior author Bernd Schnabl, MD, associate professor of gastroenterology at UC San Diego School of Medicine, “we might be able to slow the progression of alcoholic liver disease by manipulating the balance of fungal species living in a patient’s intestine.”

The researchers also conducted small preliminary studies with humans to examine intestinal fungi of people with alcohol use disorder and various stages of liver disease. They observed an overgrowth of a specific fungal species compared to healthy control subjects, as well as less fungal diversity in individuals with alcohol use disorder and ALD. They also found that the more prevalent the fungal overgrowth in individuals with ALD, the higher the likelihood of mortality.

“This work demonstrates that alcoholic liver disease is exacerbated not only by bacteria, but also by fungi. Therefore, therapeutic strategies that target both need to be translated into clinical practice,” said co-author Derrick Fouts, PhD, professor of genomic medicine at JCVI. “This study suggests a greater role of fungi in modulating the human microbiome than previously appreciated.”